Kala-azar is a slow progressing
indigenous
disease caused by a protozoan parasite of genus Leishmania

In India Leishmania donovani
is the only parasite causing this disease

The parasite primarily infects
reticuloendothelial system and may be found in abundance in
bone marrow, spleen and liver.

Post Kala-azar Dermal
Leishmaniasis (PKDL) is a condition when Leishmania
donovani invades skin cells, resides and develops there
and manifests as dermal leisions. Some of the kala-azar cases
manifests PKDL after a few years of treatment. Recently it is
believed that PKDL may appear without passing through visceral
stage. However, adequate data is yet to be generated on course
of PKDL manifestation

Skin – dry, thin and scaly
and hair may be lost. Light coloured persons show grayish
discolouration of the skin of hands, feet, abdomen and face
which gives the Indian name Kala-azar meaning “Black fever”

Anaemia – develops rapidly

Anaemia with
emaciation and gross splenomegaly produces a typical appearance
of the patients

What is Post
Kala-Azar Dermal Leishmaniasis (PKDL)?

Post Kala-azar Dermal
Leishmaniasis is a condition in which Leishmania donovani
parasites are found in skin. PKDL develops in some of the
Indian kala-azar patients usually 1-2 years or more following
recovery of Kala-azar; less commonly without suffering from
Kala-azar

What are Signs &
Symptoms of PKDL?

Types of morphological
lesions:

Early hypopigmented macules
similar to macular lesions of Lepromatous Leprosy but normally
less than 1 cm. Usually occur on face but can affect any part
of the body.

Later (after a variable
period of months or years) diffuse nodular lesions on those
macules

Erythematous butterfly rash
which may be aggravated by exposure to Sunlight; an early sign
of PKDL

Erythematous papules and
nodules which usually occur on face, especially the chin.

Parasite undergo morphological
change to become flagellate (Promastigote or Leptomonad),
development and multiplication in the gut of sandflies and
move to mouthparts

Healthy human hosts get
infection when an infective sandfly vector bites them

Kala-azar Vector in India

There is
only one sandfly vector of Kala-azar in India Phlebotomus aregentipes

Sandflies are small insects,
about one fourth of a mosquito. The length of a snadfly
body ranges from 1.5 to 3.5 mm.

Adult is a small fuzzy,
delicately proportionate fly with erect large wings. The
entire body including wings is heavily clothed with long
hairs.

Life cycle consists of egg,
four instars of larvae, pupa and adult. The whole cycle takes
more than a month, however, duration depends on temperature
and other ecological conditions

They prefer high relative
humidity, warm temperature, high subsoil water and abundance
of vegetation.

Sandflies breed in favourable
micro-climatic conditions in places with high organic matter
that serve as food for larvae

These are ecologically
sensitive insects, fragile and cannot withstand desiccation

How Kala-azar is Diagnosed?

Clinical:

A case of fever of more than 2 weeks duration
not responding to antimalarials and antibiotics. Clinical
laboratory findings may include anaemia, progressive
leucopenia
thrombocytopenia and hypergammaglobulinemia

Laboratory:

Serology tests:
Variety of tests are available for diagnosis of Kala-azar.
The most commonly used tests based on relative sensitivity;
specificity and operationally feasibility include Direct
Agglutination Test (DAT), rk39 dipstick and ELISA. However
all these tests detect IgG antibodies that are relatively
long lasting. Aldehyde Test is commonly used but it is a
non-specific test. IgM detecting tests are under development
and not available for field use.

Parasite demonstration in bone
marrow/spleen/lymphnode aspiration or in culture medium is
the confirmatory diagnosis. However, sensitivity varies with
the organ selected for aspiration. Though spleen aspiration
has the highest sensitivity and specificity (considered gold
standard) but a skilled professional with appropriate
precaustions can perform it only at a good hospital facility.

- Amphotericin B 1mg/kg b.w. IV infusion daily or
alternate day for 15-20 infusions. Dose can be increased in
patients

with incomplete response with 30
injections

B. SSG and Miltefosine Failures

-
Liposomal Amphotericin B (when final results are available with
proven efficacy and safety)

Treatment of PKDL

SSG
in usual dosages for KA could be given up to 120 days

Repeated 3-4 courses of
Amphotericin B can be given in patients failing SSG treatment

What is the extent of problem of
Kala-azar in India?

Endemic in eastern States
of India namely Bihar, Jharkhand, Uttar Pradesh and West
Bengal

48 districts endemic;
sporadic cases reported from a few other districts

Estimated 165.4 million
population at risk in 4 states

Mostly poor socio-economic
groups of population primarily living in rural areas are
affected

Kala-azar Control Efforts in
India

An organized centrally
sponsored Control Programme launched in endemic areas in
1990-91

Government of India provided
kala-azar medicines, insecticides and technical support and
the State governments implemented the programme through
primary health care system and district/zonal and State
malaria control organizations and provided other costs
involved in strategy implementation

Programme strategy included:

-
Vector control through IRS with DDT up to 6 feet height from the
ground twice annually

- Early Diagnosis and Complete treatment

- Information Education Communication

-
Capacity Building

Programme intensified in
1991-92 which led to improved case registration through
primary health care system